Apparatus for pressing chipboard panels

ABSTRACT

A multi-deck heating press having vertical frame members at spaced points along its length, and conduits carrying liquid heating medium for the individual press decks, which pass close alongside some of these frame members, causing them to heat up, while other frame members remain cool. To eliminate differential thermal expansion due to some vertical frame members being heated while others remain cool, the said frame members have passageways provided therein, and fluid medium is circulated through these passageways. In one embodiment, heating medium is circulated through the cold frame members; in another coolant is circulated through the heated frame members; and in a third form, heating medium is circulated through some frame members and coolant through others. All vertical frame members of the press are brought to substantially the same temperature by the fluid medium, thereby eliminating thermal distortion in the press.

United States Patent [191 Hiitter APPARATUS FOR PRESSING CHIPBOARDPANELS [75] Inventor: Wilhelm Hiitter, Krefeld, Germany [73] Assignee:Becker & van Hullen Niederrheinische Maschinenfabrik, Krefeld, Germany22 Filed: June 7,1972 211 App]. No.: 260,671

[30] Foreign Application Priority Data in] 3,826,601 14 July 30, 19743,482,510 12/1969 Fickler l00/93P Primary Examiner-Robert L. Spicer, Jr.Attorney, Agent, or Firm-'-Herbert E. Kidder [5 7] ABSTRACT A multi-deckheating press having vertical frame members at spaced points along itslength, and conduits carrying liquid heating medium for the individualpress decks, which pass close alongside some of these frame members,causing them to heat up, while other frame members remain cool. Toeliminate differential thermal expansion due to some vertical framemembers being heated while others remain cool, the said frame membershave passageways provided therein, and fluid medium is circulatedthrough these passageways. In one embodiment, heating medium iscirculated through the cold frame members; in another coolant iscirculated through the heated frame mem bers; and in a third form,heating medium is circulated through some frame members and coolantthrough others. All vertical frame members of the press are brought tosubstantially the same temperature by the fluid medium, therebyeliminating thermal distortion in the press.

5 Claims, 3 Drawing Figures PATEmwJmsomu SHEEI 3 BF 3 Fig. 3

APPARATUS FOR PRESSING CHIPBOARD PANELS The invention relates to amethod for the manufacture of chipboard panelsin a multi-deck heatingpress wherein a heating medium is fed through the individual pressdecks, as well as to a press for carrying out this method.

As a rule, a multi-deck press has several press frames mounted insuccession in the longitudinal direction of the press which consistessentially of vertical parts firmly attached in pairs opposite eachother and which are connected together on their upper sides by ahorizontally attached connecting member. The individual press decks aremounted so as to be vertically displaceable within the press frames. Afull-length plate serving as the press bolster is attached at thehorizontal connecting parts. In order to fill the press with aweb ofchips, the individual press decks are each lowered sufficiently to allowthe individual press decks to be filled. The press decks are then raiseduntil the uppermost deck abuts the press bolster and the decks mountedtherebeneath, or the web of chips mounted thereon, abut the lower sidesof each deck lying thereabove. Thus, as a result of heating theindividual press decks, the manufacture of chipboard panels takes placein known manner through the effect of heat and pressure.

The supply of the heating medium to the individual press decks inpresses of the usual construction is by way of vertically arrangedsupply pipes which are connected at their upper ends with cross-pipes.The crosspipes are in turn connected with the heating channels in theindividual press decks. The cross-pipes are firmly attached to theheating plates and are moreover fixedly connected with the supply pipes.The cross-pipes consequently move up and down with the individual decksduring opening and closing of the multi-deck heating press.,The supplypipes terminate at their lower side in the press pit and are thereconnected with flexible hoses which enable the necessary lengthcompensation to be effected.

In addition to the pipes for supplying the heating medium, correspondingpipes are provided for the removal of the heating medium after it hasflowed through the heating channels in the individual press decks.

The pipes for the supply or transfer of the heating medium lierelatively close to each other on the longitudinal sides of the press;the pipes for the supply of heating medium are provided at onelongitudinal side of the press whilst the pipes for transferring theheating medium are provided at the other longitudinal side thereof. Thisarrangement means that the press frames lying in the region of theheating pipes, namely in particular the vertical parts of the pressframes, are heated. The vertical parts of the press frames adjacenttheheating tubes therefore assume a higher temperature than the pressframes which are not directly adjacent the heating pipesSince theheating medium in the heating pipes has a temperature of the magnitudeof 180C, the vertical parts of the press frames adjacent the heatingpipes assumeatemperature which is indeed less than 180 C, but lieshowever considerably above the temperature of the remaining pressframes. Often the multi-deck heating presses are mounted in draughtypassageways which has the result that the press frames not directlyadjacent the heating pipes are cooled down as a result of the draught.

Owing to the temperature difference between the vertical parts of thepress frames adjacent the heating pipes and the remaining press frames,the thermal expansion in the vertical parts of the press frames adjacentthe heating pipes is greater than the thermal expansion in the remainingpress frames.

This has the result that the plate-like press bolster firmly attached tothe cross-member of the press frames is distorted owing to the thermalexpansion of the verticle parts of the press frames adjacent the heatingpipes. If for example the heating pipes are attached on the longitudinalsides of the heat press so as to be axially opposite each other, thepress bolster undergoes arcuate working, such that, seen from the inletto the press in the longitudinal direction thereof, the press bolster isat first fiat, then in the region of the press frames with higherthermal expansion is deflected upwardly in the form of a curve andfinally lies again in the plane corresponding to the inlet region.

During pressing of the chipboard panels, the chip board panel producedon the uppermost press deck is therefore distorted in a mannercorresponding to the deformation of the press bolster. This distortionis transferred to the individual deck located beneath it, since thelower press decks match the shape of each daylight mounted above them.This results in the chipboard panels manufactured on a multi-daylightheating press of this kind being of various thicknesses.

It is an object of the invention to avoid the deformation of the upperpress bolster and thus to enable the manufacture of chipboard panels ofequal thickness in a multi-daylight heating press.

It is endeavoured to achieve this object in accordance with theinvention by keeping the vertical parts of the press frames or, in theevent of column presses,

. the press columns, at an even temperature. It thus happens that allthe vertical parts of the press frames or the press columns alwaysundergo the same thermal expansion and consequently arcuate deformationof the upper press bolster does not occur.

For simplicity, the following constantly relates to press frames. Themeasures described for the press frames can however be suitably appliedto the columns of column presses.

Since the temperature of the heating medium supplied to the heatingchannels in the press daylights hardly differs from the temperature ofthe heating me dium emerging on the opposite side of the press, ac,-cording to a further feature of the invention the vertical parts of thepress frames of both longitudinal sides of the press are kept at thesame temperature.

The method according to the invention can be carried out in variousways. Thus, aheating medium may be supplied to the vertical parts of thepress frames for example so that the vertical parts of the press framesare heated to the temperature of the vertical parts having the highesttemperatures owing to the supply and transfer of the heating mediumtothe press decks.

According to a further feature of the invention, a

cooling medium may be supplied to the press frames.

Ina suitable example of this proposal, the vertical parts of the pressframes heated as a result of the supply or transfer of the heatingmedium to the press decks are cooled down'to the temperature of thevertical parts of the remaining press frames.

According to a further feature of the invention, a cooling medium may besupplied to the vertical parts of the press frames which are heated as aresult of the supply or transfer of the heating medium to the pressframes and a heating medium may be supplied to the vertical parts of theremaining press frames.

The device for carrying out the method according to the invention ischaracterized in that channels are arranged in at least the verticalparts of the press frames of a multi-deck heating press, a heatingmedium and/or cooling medium being passed through those channels.

According to a further feature of the invention, the heating mediumwhich serves to heat up the individual press decks flows through thechannels.

According to another feature of the invention, the channels provided inthe vertical parts of the press frames are interconnected so that aclosed heating or cooling circuit, or several closed heating or coolingcircuits, can be formed for the vertical parts of the press frames.

In a further embodiment of the invention, the channels are only providedin the vertical parts of the press frames which are heated as a resultof the supply of heating medium to the press decks. In this case, acooling medium is passed through the channels, namely so that thevertical parts provided with the channels are cooled down to thetemperature of the remaining vertical parts of the press frames.

According to a further feature of the invention, the channels may onlybe provided in the vertical parts of the press frames which are notheated as a result of the supply of the heating medium to the pressdecks. In this case, a heating medium is passed through the channels,namely so that the vertical parts of the press frames provided with thechannels assume the same temperature as the vertical parts of the pressframes heated by the supply of the heating medium to the press decks.

A further possibility for carrying out the method according to theinvention exists in that the channels are provided in elements, by wayof example attached plates, tubes or the like provided on the verticalparts of the press.

Furthermore there is'the possibility of electrically heating thevertical parts whereby a regulating device which can be controlled bythe maximum temperature of a vertical part is provided for the heatingdevice.

Preferred embodiment of the invention to be described by way of exampleis illustrated in the drawings in which:

FIG. 1 is a diagrammatic end view of a multi-deck heating press with asimultaneous closing apparatus;

FlG.-2 is a diagrammatic side view of the arrangement according to FIG.1, in which however the ends of the press and the lower part of thepress are not illustrated;

FIG. 3 is a simplified illustration of the cross-section of a pressframe according to line Ill-III of FIG. 2.

In the multi-deck heating press illustrated in the drawing, severalpress frames 1 are provided in succession in the longitudinal directionof the press and consist of vertical parts 2 and a horizontal part ortop member 3 connecting the vertical parts 2. A plate-like press bolster4'is attached to the horizontal part in the longitudinal direction ofthe press.

Vertically displaceable individual press decks 5 are provided within thepress frames 1 and the press bolster 4. The press is illustrated in theopen state on the left of FIG. 1, and in the closed state on the rightof FIG. 1. The press decks 5 are therefore indicated in the right halfof the drawing by reference symbol 5a. A press table or horizontalbottom member 7 which is vertically movable by means of the piston 6 isprovided beneath the press decks. Simultaneous closing devices 8 whichare pivotally connected to the upper press beam 19 on opposite sides ofthe press engage on the individual press decks 5 and the press table 7.The simultaneous closing devices 8 have pivotal arms 9 provided at theirends with hinged pressure rods 10 which are hingedly fastened at theirother end to the press table 7. The individual press decks 5 arehingedly connected with the pivotal arms 9 by suitably mounted tie-rods11. The tierod 11 thereby engage the relevant pivotal arm 9 in thesequence of the individual press decks 5, seen from bottom to top, atproportionally increasing spacing from the pivotal axis. Further detailsregarding the construction and function of the simultaneous closingdevices 8 are apparent for example from our German Pat. No. 1,198,057.

When the press is open (left-hand side of FIG. 1), a web of chips 12 isapplied to the individual daylights. The press is then closed(right-hand side of FIG. 1). The web of chips located on the uppermostdaylight 5a thereby abuts the press bolster 4 and the web located in thedaylight mounted beneath it abuts the lower sides of the press daylightsmounted above it. The web of chips located on the uppermost daylight 5athereby abuts the press bolster 4 and the web located in the daylightmounted beneath it abuts the lower sides of the press daylights mountedabove it. The web of chips is pressed into chipboard panels 13 throughthe effect of pressure and heat.

Heating channels (not shown), through which a heating medium flows, areprovided in the individual press decks for the heating thereof. Thesupply of heating medium to the individual press decks 5 takes place viapipe system 14 mounted at one longitudinal side of the press while theremoval of the heating medium takes place via the pipe system 15 mountedat the opposite longitudinal side of the press. The pipe systems 14 and15 correspond with each other so that only the pipe system 14 will bedescribed below. i

The pipe system 14 comprises a row of heating pipes 16 verticallymounted. near the press and which are provided for supplying the heatingmedium to a press deck 5. The heating pipes 16 open at the upper endinto transverse pipes 17 which in turn are connected with the heatingchannels (not shown) in the individual press decks. The pipes 16 and 17thus move up and down with the individual press decks 5 during openingand closing of the press. The pipes 16 terminate at their lower side(not shown) in the press pit (not shown) and are there connected by'flexible hoses which enable a length compensation and through which theheating medium is passed at the same time to the pipes 16. After flowingthrough the heating channels in the individual press decks 5, theheating medium is again drawn off via the pipe system 15 correspondingto the pipe system 14.

The pipe systems 14 and 15 are mounted near the vertical parts 2 of afew press frames 1. The adjacent verticals of the press frames in thepipe systems are marked by 2a in FIG. 2. Since the vertical parts 2a aremounted nearthe pipe systems 14, 15 the latter are heated as a result ofthe effect of the heating medium passing through the pipe system, namelyto an essen tially higher temperature than the temperature of theremaining vertical parts 2. Owing to the thermal expansion which therebyoccurs in the longitudinal direction of the vertical parts 2a, the pressbolster 4 firmly attached thereto is arcuately distorted in the regionof the vertical parts 2a, so that the press bolster 4 is no longer flat.Consequently, the chipboard panels pressed on such a press would be ofdifferent thickness.

Tocarry out the proposal according to the invention, namely to keep thevertical parts of the press frames at the same temperature in order toavoid this disadvantage, channels 18 are provided in the vertical parts2 of the press frames and a medium is supplied to the vertical partsthrough said channels 18 according to the arrows in FIG. 3, which mediumenables the desired temperature compensation to be achieved between thevertical parts 2a and the remaining vertical parts 2 in order to achievean even as possible temperature of the vertical parts. This medium canbe a heating medium with which the vertical parts 2 are heated to thetemperature of the vertical parts 2a, or may be a-cooling medium withwhich the heat absorbed from the vertical parts 2a by the pipe systems14' and 15 can be dissipated. The channels 18 of the individual verticalparts 2, 2a are preferably connected together at least on onelongitudinal side of the press so that one or more closed heating orcooling circuits ensue for the vertical parts of the press frames. Ifthe vertical parts 2, 2a all have the same temperature, the thermalexpansion of these vertical parts in the longitudinal direction is alsoequal, and thus the undesired deformation of the press bolster 4 cannotarise.

I claim:

1. A multi-deck heating press for the manufacture of chipboard panels orthe like, comprising:

a press frame having a plurality of laterally spaced vertical partswhich are connected together at their top ends by a horizontal topmember, and at their bottom ends by a horizontal bottom member, said topand bottom members being normally parallel to one another;

a plurality of vertically spaced press decks disposed between saidvertical parts and stacked between said top and bottom members, saiddecks being movable vertically with respect to said frame and alsomovable vertically with respect to one another;

means for heating said press decks up to operational temperature;

means for closing said press decks uniformly together in the verticaldirection;

thermal sources located closely adjacent certain of said vertical partsof said frame, which tend to radiate heat to said certain verticalparts; and

means for equalizing the temperature of all of said vertical parts ofsaid frame to counteract the unequali'zed' heating effects caused bysaid thermal sources, so that said vertical parts are all caused toexpand equal amounts, thereby preserving parallelism between said topand bottom members, and between said deck plates.

2. A multi-deck heating press as in claim 1, wherein said thermal sourcecomprises conduits carrying liquid heating medium from a source ofsupply to said press decks, where the heating medium is circulatedthrough channels in the decks to heat up the decks.

3. A multi-deck heating press as in claim 1, wherein said means forequalizing the temperature of all of said vertical parts compriseschannels provided in the vertical parts through which liquidheat-exchange medium is circulated, said liquid heat-exchange mediumbringing all of said vertical parts to a uniform temperature.

4. A multi-deck heating press as in claim 2, wherein said means forequalizing the temperature of all of said vertical parts compriseschannels provided in the vertical parts through which said liquidheating medium is circulated so as to heat up all of said vertical partsto a uniform temperature.

5. A multi-deck heating press as in claim 1, wherein said certainvertical parts have channels provided therein, and wherein said meansfor equalizing the temperature of all of said vertical parts comprises asource of liquid coolant connected to said channels in said certainvertical parts, whereby said certain vertical parts are cooled to removethe heat added by said thermal source.

1. A multi-deck heating press for the manufacture of chipboard panels orthe like, comprising: a press frame having a plurality of laterallyspaced vertical parts which are connected together at their top ends bya horizontal top member, and at their bottom ends by a horizontal bottommember, said top and bottom members being normally parallel to oneanother; a plurality of vertically spaced press decks disposed betweensaid vertical parts and stacked between said top and bottom members,said decks being movable vertically with respect to said frame and alsomovable vertically with respect to one another; means for heating saidpress decks up to operational temperature; means for closing said pressdecks uniformly together in the vertical direction; thermal sourceslocated closely adjacent certain of said vertical parts of said frame,which tend to radiate heat to said certain vertical parts; and means forequalizing the temperature of all of said vertical parts of said frameto counteract the unequalized heating effects caused by said thermalsources, so that said vertical parts are all caused to expand equalamounts, thereby preserving parallelism between said top and bottommembers, and between said deck plates.
 2. A multi-deck heating press asin claim 1, wherein said thermal source comprises conduits carryingliquid heating medium from a source of supply to said press decks, wherethe heating medium is circulated through channels in the decks to heatup the decks.
 3. A multi-deck heating press as in claim 1, wherein saidmeans for equalizing the temperature of all of said vertical partscomprises channels provided in the vertical parts through which liquidheat-exchange medium is circulated, said liquid heat-exchange mediumbringing all of said vertical parts to a uniform temperature.
 4. Amulti-deck heating press as in claim 2, wherein said means forequalizing the temperature of all of said vertical parts compriseschannels provided in the vertical parts through which said liquidheating medium is circulated so as to heat up all of said vertical partsto a uniform temperature.
 5. A multi-deck heating press as in claim 1,wherein said certain vertical parts have channels provided therein, andwherein said means for equalizing the temperature of all of saidvertical parts comprises a source of liquid coolant connected to saidchannels in said certain vertical parts, whereby said certain verticalparts are cooled to remove the heat added by said thermal source.